Beta

×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

LiftPort Wants To Build Space Elevator On the Moon By 2020

Soulskill posted about 2 years ago | from the now-we-just-have-to-get-to-the-moon dept.

Moon 210

Zothecula writes "When the late Neil Armstrong and the crew of Apollo 11 went to the Moon, they did so sitting atop a rocket the size of a skyscraper that blasted out jets of smoke and flame as it hurtled skyward. For over half a century, that is how all astronauts have gone into space. It's all very dramatic, but it's also expensive. Wouldn't it be cheaper and easier to take the elevator? That's the question that Michael Laine, CEO of LiftPort in Seattle, Washington, hopes to answer with the development of a transportation system that swaps space-rockets for space-ribbons. LiftPort ultimately wants to build a space elevator on Earth, but the company isn't planning on doing it in one go. Instead, Laine and his team are settling for a more modest goal – building an elevator on the Moon by 2020. This is much easier. For one thing, there’s no air on the Moon, so no icing problems. Also, the lower gravity means that no unobtainium is needed for the ribbon. Kevlar is strong enough for the job. And finally, there’s very little in the way of satellites or debris to contend with."

cancel ×

210 comments

Sorry! There are no comments related to the filter you selected.

The goal of the project? (1)

Anonymous Coward | about 2 years ago | (#41157577)

If it's for profit, how does it make money?
If it's not, is the point to prove it's possible and learn more about how to build one?

Re:The goal of the project? (1)

neminem (561346) | about 2 years ago | (#41158055)

I assume the latter. I mean, when I'm programming a new component, I often start with the easier component while I'm figuring out the harder stuff, even if the harder stuff could be useable by itself and the easier stuff requires the harder stuff to work (at which point I would just put up a placeholder for testing purposes). Granted, I'm talking about days of one developer's time rather than years of a whole company's, but the principle is similar. Once you had a terrestrial space elevator, you'd want a lunar one too, so might as well practice on the easy target first.

But yes, I was also depressed, when I just saw "[company] wants to build space elevator by 2020", and missed the "on the moon" originally. I was all excited that we might actually see a useful space elevator in my lifetime. (Useful in this case being defined as "would let me exit earth's atmosphere at the cost of less than a bajillion dollars per trip.")

Re:The goal of the project? (2)

cbhacking (979169) | about 2 years ago | (#41159281)

Liftport has been around for a while, but they've run into a number of troubles. I don't know what your age or life expectancy is, but if you take their roadmap seriously, it's quite possible that there will still be a space elevator in your lifetime.

Of course, if you take their roadmap without a pretty serious grain of salt, you probably haven't been following them for the last six or so years. It's been adjusted backward many times.

Re:The goal of the project? (2)

Tuidjy (321055) | about 2 years ago | (#41158177)

It's not for profit, because there's nothing worth lifting off the Moon.

It will not work as a proof of concept, because what we learn from it will not apply to a space elevator anchored on Earth.

Maybe I should elaborate on the this. The Moon rotates slowly. Remember, the same side always faces the Earth, thus its rotation period is the same as its orbital period. So for a space elevator to stay up, it would have to be quite long, anchored at an equatorial point facing Earth, and the higher end would have to be close enough to Earth for the forces to balance. (Attraction from Earth, attraction from the Moon, pull exerted by the string/rail...)

I am not a physicist, nor have I done the math. I do not even know whether the above setup is workable. But I do not believe that another setup is even remotely possible, and I do know that we would not learn much about building an elevator from Earth even if we built an elevator from the Moon in the above fashion.

Basically, I believe this is bullshit. Now that I have probably revealed my ignorance, I'll go and RTFA. Probably I'll learn that the summary's misleading.

Re:The goal of the project? (5, Insightful)

History's Coming To (1059484) | about 2 years ago | (#41158517)

There's plenty worth lifting off the moon, if we can do it. There's water for starters, plus plenty of raw materials for making high quality metals, ceramics, semiconductors and so on. If you can send them into a low Earth orbit then you'll probably find you can beat the per-kilo costs of launching similar material from Earth, what with the big gravity well and atmosphere and all. If you can undercut an entire planet then I'd call that a worthwhile business opportunity. Can't see how a space elevator helps much, but there's plenty worth lifting off the moon.

Re:The goal of the project? (1)

Jahf (21968) | about 2 years ago | (#41159359)

3He will power the world!

Re:The goal of the project? (1)

History's Coming To (1059484) | about 2 years ago | (#41158411)

I would imagine so, I can't think of a "killer app" that isn't easier to do with an electromagnetic mass driver, and for exactly the same reasons (near vacuum, low gravity), except for possibly the power requirements.

Re:The goal of the project? (0)

Anonymous Coward | about 2 years ago | (#41158875)

If it's for profit, how does it make money?
If it's not, is the point to prove it's possible and learn more about how to build one?

The point is to keep moving money from the enthusiastically gullible to Michael Laine.

Re:The goal of the project? (1)

slacka (713188) | about 2 years ago | (#41158925)

Why are they asking for money on kickstart, when they could save a ton just by switching from helium to hydrogen weather balloons? Sure they have to take some extra precautions because it's flammable (NOT explosive, google it) , but the cost saving will more that make up for it. In addition they are helping to preserve a precious resource necessary for things like MRIs.

Space elevator orbiting the moon? (1, Informative)

Ken_g6 (775014) | about 2 years ago | (#41157579)

First post? Anyway, you can't "anchor" a space elevator to the moon from lunar orbit. It would have to stretch all the way to the Earth - or at least to a Lagrange point.

Re:Space elevator orbiting the moon? (0)

Anonymous Coward | about 2 years ago | (#41157609)

No, you hang it from a satellite that is in geostationary orbit around the moon. No lagrange point needed.

Re:Space elevator orbiting the moon? (1)

Nadaka (224565) | about 2 years ago | (#41157705)

The moons rotational period is its orbital period. There is no orbit around the moon that is "geosynchronous".

Re:Space elevator orbiting the moon? (2)

History's Coming To (1059484) | about 2 years ago | (#41158575)

Correct, it's tidally bound to the Earth, you'd need to "anchor" it at, or beyond, L1.

Re:Space elevator orbiting the moon? (2)

symbolset (646467) | about 2 years ago | (#41159367)

L2 might work better as you could use the additional leverage to assist launching stuff out of cislunar space.

Re:Space elevator orbiting the moon? (0)

Anonymous Coward | about 2 years ago | (#41157711)

The moon doesn't rotate much (every 28ish days). So your object won't have much velocity. And if it's basically just sitting out there, barely orbiting, the Earth's gravity is going to yank it all over the place.

I think a luna-stationary orbit might be harder than it looks.

Re:Space elevator orbiting the moon? (2)

ClickOnThis (137803) | about 2 years ago | (#41157725)

No, you hang it from a satellite that is in geostationary orbit around the moon. No lagrange point needed.

The moon rotates once every 28 days, not 24 hours. Too lazy to calculate the numbers, but I think a lunastationary orbit would have a ridiculously long radius. Not practical. Better do do what the GP suggests: put the upper part at Lagrange point.

There is some additional information in this article [universetoday.com] .

Re:Space elevator orbiting the moon? (1)

randall77 (1069956) | about 2 years ago | (#41157833)

The upper point needs to be beyond the Lagrange point in order to hold up the elevator. Probably well beyond, depending on its mass relative to the cable.

Re:Space elevator orbiting the moon? (3, Insightful)

CrimsonAvenger (580665) | about 2 years ago | (#41157907)

The moon rotates once every 28 days, not 24 hours. Too lazy to calculate the numbers, but I think a lunastationary orbit would have a ridiculously long radius. Not practical. Better do do what the GP suggests: put the upper part at Lagrange point.

A lunastationary orbit would have a radius of ~384400 km (the distance from Earth to the Moon).

If you put the upper point at L1 or L2, you'll still have to put an anchor farther out to keep tension on the cable. Which may or may not be really useful, but it's an interesting idea, anyway.

Re:Space elevator orbiting the moon? (1)

cyborg666 (2488892) | about 2 years ago | (#41159489)

If you anchor the elevator on the far side, wouldn't it be "flung out" by the motion of the moons orbit, thus reducing the lunarstationary radius?

Re:Space elevator orbiting the moon? (0)

Anonymous Coward | about 2 years ago | (#41158585)

WTFV. That is exactly what they propose to do. The upper end would be at L1.

Re:Space elevator orbiting the moon? (1)

Aviation Pete (252403) | about 2 years ago | (#41158085)

No, you hang it from a satellite that is in geostationary orbit around the moon. No lagrange point needed.

Make this "lunarstationary orbit", and you are correct.

Re:Space elevator orbiting the moon? (0)

Anonymous Coward | about 2 years ago | (#41158369)

Huh?

If you hang the thing from an orbiting satellite, the cable will drag the satellite back to the surface. It's heavy.

Space elevators don't hang. They use a weight being swung around using the body's rotation, and the weight is, by necessity, a long way the other side of the X-stationary orbit.

Re:Space elevator orbiting the moon? (4, Informative)

Time_Ngler (564671) | about 2 years ago | (#41157831)

They said Space elevator. Space elevator "orbiting the moon" are your words. This link shows exactly what they are attempting to do: http://www.gizmag.com/lunar-elevator/23884/pictures#2 [gizmag.com]

The Moon is Blue (3, Insightful)

fm6 (162816) | about 2 years ago | (#41157903)

My orbital mechanics sucks, but apparently smarter people have thought this through. It's not as intuitively simple as a tether between the Earth's equator and a geostationary satellite, but the physics does work:

http://en.wikipedia.org/wiki/Lunar_space_elevator [wikipedia.org]

My issue is that this is yet another fancy space project that presupposes an earth to high-orbit launching capability we don't have, nobody is seriously working on, and would seem to require more financial support than anybody has the will to deliver.

If somebody can crack this nut, then we can start talking about lunar space elevators, missions to other planets, and other fun stuff. But until that happens, all these fancy proposals are just so much hot air.

Re:Space elevator orbiting the moon? (1)

Nethemas the Great (909900) | about 2 years ago | (#41158065)

It "might" require an anchor at L1 or L2. We're not used to thinking of building tethers that long and so it seems silly but I'm not sure it's quite as impractical as it sounds. It's just a matter of weaving fibers together until desired length is achieved. Why I say "might" though with respect to needing to anchor at L1 or L2 is that I can see alternatives that compensate. To my understanding all that is required is the ability to hold the tether taut. This can be achieved with length, anchor mass, or I would suggest possibly propulsion. A reaction engine could be used that uses the very aluminum harvested from the regolith as fuel. Or, potentially a solar sail could be used that would effectively turn the anchor into a solar kite.

Re:Space elevator orbiting the moon? (1)

Zordak (123132) | about 2 years ago | (#41159365)

Two of my imaginary friends reproduced once ... with negative results.

I'm confused. Wouldn't the result be positive?

Re:Space elevator orbiting the moon? (1)

symbolset (646467) | about 2 years ago | (#41159237)

Correct. This would work on 1 Ceres though. I was trying to figure the math on that one a few months ago.

well that's just silly (0)

swell (195815) | about 2 years ago | (#41157589)

don't you think?

Re:well that's just silly (3, Insightful)

Nethemas the Great (909900) | about 2 years ago | (#41157687)

Well I'm not so sure... It would make transport on and off the surface cheaper. This would in turn make it more economical to conduct mining operations on the the moon--which is presently our easiest to access source of Helium-3.

Re:well that's just silly (1)

swell (195815) | about 2 years ago | (#41157851)

"make it more economical to conduct mining operations on the the moon"

OK, but I'm having difficulty imagining massive mining machines working their way along the tether. And how to begin the process from an orbiting craft. And then, once landed, how will these machines get the energy necessary for mining operations?

I'm obviously missing some essential information about why this might be practical.

Re:well that's just silly (4, Insightful)

Nethemas the Great (909900) | about 2 years ago | (#41159225)

The mining machines wouldn't necessarily need to be: massive, transported via the tether, and/or come down fully assembled. Not everything has to start out on massive scales. For instance consider the state of global shipping back in the 18th century then compare that to the early 21st. Or farming in the 18th vs. 21st. Normally things start out small and gradually build out as technology and resources develop. Staging things is simply an engineering problem which if Curiosity is any indicator we seem to be getting pretty good at. Even during the Apollo missions we were dropping some pretty serious hardware down onto the moon. Powering these machines can come from any number of technologies from mundane to exotic. We already have well proven solar and RTG technologies, there are a few rather interesting possibilities using in-situ resources as well. For instance using the newly discovered water with the aluminum in the regolith to produce hydrogen for fuel [smartplanet.com] . The Aluminum Hydroxide byproduct has its own interesting uses. The obvious one is of course simply using the mined He-3 for fusion power (whenever we get that one figured out).

Few grand adventures into human frontiers are ever "practical" initially and that unfortunately prevents people from seeing what humanity's pioneers and explorers see. In the 1800's no one got what Charles Babbage saw. During the first half of the 1900's very few saw what Konrad Zuse saw. Today no one can miss it and everyone demands it. People too often are quick to see problems as "too hard", too near-sighted to see possibilities, too self-centered to appreciate the benefits to others. You might not get to holiday on Utopia Planitia, or sail the methane seas of Titan but wouldn't it be awesome to initiate the projects now that make that a reality for your progeny? Both incomprehensible business opportunities and human delights await us on this next frontier. What are we waiting for?

Re:well that's just silly (2, Insightful)

bertok (226922) | about 2 years ago | (#41157967)

Except that it's not economical: all current plans for fusion power intend to breed the required fuel isotopes from lithium, which is several orders of magnitude cheaper than mining anything from space.

So, that leaves what? Nothing. There is nothing on the Moon even remotely worth the multi-trillion-dollar expense. It's just rocks in a vacuum. We've got plenty of rocks here!

Re:well that's just silly (4, Insightful)

Nethemas the Great (909900) | about 2 years ago | (#41158525)

Similar ideas were had about computers and a great many other things. Sometimes the destination is a bit farther from you than your myopic vision permits to be seen. I also didn't say "economical" relative to earth bound alternatives but then you're also making the assumption that we're taking this stuff back to earth. Let's throw a few points up that you might not be considering:
  • He-3 is preferable for a fusion fuel since it's aneutronic--no radiation to deal. It comes that way from the moon, the path to producing it on earth does everything but avoid radiation.
  • He-3 is useful as an advanced fuel in rocket propulsion
  • Power can be produced in space and beamed down to earth
  • Many of those rocks we have down here on Earth resulted from really big rocks from space slamming into us. Might be good idea if we have technology, infrastructure and humanity already in space before we're in need of it.
  • Putting multi-trillions of dollars into the vacuum is preferable to craters into the middle-eastern sand. The same jobs are created but at the end of the day at you have something far more impressive to show for it and far fewer lives expended.

Re:well that's just silly (2, Insightful)

bertok (226922) | about 2 years ago | (#41159127)

He-3 is preferable for a fusion fuel since it's aneutronic--no radiation to deal. It comes that way from the moon, the path to producing it on earth does everything but avoid radiation.

Even the "aneutronic" fusion reactions have side-reactions that produce neutrons [wikipedia.org] . While a lower neutron flux helps with materials engineering from a longevity standpoint, it still makes the reactor wall materials radioactive. That's the real problem, and He-3 doesn't fix it.

He-3 is useful as an advanced fuel in rocket propulsion

a) Requires technology that is currently at the wishful-thinking stage of development.
b) Rockets don't require aneutronic fusion, because fusion engines would be most useful in deep space, where radiation is not a problem.
c) He-3 fusion isn't entirely aneutronic anyway.
d) He-3 fusion is harder than D-T fusion.

Power can be produced in space and beamed down to earth

Has nothing to do with the Moon, or an orbital tether.

There is no realistic source of power that either exists only on the Moon, or would be cheaper to produce on the Moon.

Many of those rocks we have down here on Earth resulted from really big rocks from space slamming into us. Might be good idea if we have technology, infrastructure and humanity already in space before we're in need of it.

A tether on the Moon won't help you solve this problem. If this comes up, robotic space-probe technology will be all we need, and we have that already. Stop watching Hollywood sci-fi where brave men have to go deal with the problem in a giant space ship. The real solution will likely be as simple as coating one side of the incoming object with soot.

Putting multi-trillions of dollars into the vacuum is preferable to craters into the middle-eastern sand. The same jobs are created but at the end of the day at you have something far more impressive to show for it and far fewer lives expended.

[citation needed]

Things aren't that simple in the real world. As cold and sad as it is, the lives of brown people in a distant desert just aren't worth much to anybody in the United States, unlike the oil they live on top of. By some calculation it was worth it to invade. Thanks to various mistakes, the cost ended up spiralling out of control, but even so the wars are probably a better investment than going to the Moon.

He-3 is worthless, because it doesn't achieve aneutronic fusion, just slightly-less-neutronic fusion. So then, what's left on the Moon that's worth a multi-trillion investment?

Seriously, name one thing that's on the moon that you think is worth trillions of dollars, keeping in mind that its surface is entirely covered in rocks.

Re:well that's just silly (1)

Nethemas the Great (909900) | about 2 years ago | (#41159305)

Forming those rocks into a stepping stone.

Re:well that's just silly (1)

Anonymous Coward | about 2 years ago | (#41158785)

So, that leaves what? Nothing. There is nothing on the Moon even remotely worth the multi-trillion-dollar expense. It's just rocks in a vacuum. We've got plenty of rocks here!

Using lunar material for construction projects in space is MUCH easier than getting any significant quantities from the deep well Earth is in.

Example projects:
* ridiculously large & light zero-g free-floating solar arrays with uninterrupted sunlight
* space habitats & manufacturing plants
* spaceships

Re:well that's just silly (1)

Anonymous Coward | about 2 years ago | (#41159031)

It would be much cheaper to get stuff from the Moon to the ISS than from Earth. If it became feasible to extract water from the Moon that could be enough to justify it.

Re:well that's just silly (1)

joe_frisch (1366229) | about 2 years ago | (#41158647)

The reason that the elevator can work without unobtainium is that its EASY to get off the moon. The delta-v required is withing the range of all sorts of technologies (rockets - don't even need H2, could probably use O2 or N2 exhaust), mass drivers, etc.

This project would be insanely expensive - need to get the elevator (still a multi-thousand km structure) to the moon, set up etc.

Insane to think it could be done in 8 years.

Once you've done all that, there just isn't that much you really want from the moon. He3 is a somewhat better fusion fuel than D-T, but we are still at least several decades and several 10s of billions of dollars (probably MUCH more) away from fusion.

Just build it horizontally (1)

ShanghaiBill (739463) | about 2 years ago | (#41157597)

The Earth has an atmosphere, so a space elevator needs to go up to get out of it. On the Moon, there is no atmosphere, so the you can just build a mass driver [wikipedia.org] horizontally, along the ground, and launch stuff in a tangential trajectory.

Re:Just build it horizontally (1)

LurkerXXX (667952) | about 2 years ago | (#41157657)

Space elevators also allow you to bring things gently DOWN from orbit. How's that mass driver gonna work for ya?

Re:Just build it horizontally (1)

ZombieBraintrust (1685608) | about 2 years ago | (#41157825)

No sure how a space elevator is going to bring something gently down assuming the object was launched at the moon from the earth. Your going to have to slow down quite a bit to dock with an elevator. Might as well use that energy to land on the surface. Plus you run the risk of damaging the elevator if you attempt to dock things with it.

Re:Just build it horizontally (3, Informative)

ShanghaiBill (739463) | about 2 years ago | (#41157953)

Space elevators also allow you to bring things gently DOWN from orbit. How's that mass driver gonna work for ya?

It could work quite well. Mass drivers can decelerate as well, and can recover and convert the kinetic energy to electricity in the process.

Re:Just build it horizontally (5, Insightful)

randall77 (1069956) | about 2 years ago | (#41158027)

Because catching a bullet with a gun is just as easy as shooting a bullet from a gun...

Re:Just build it horizontally (0)

Anonymous Coward | about 2 years ago | (#41158545)

I think an aircraft carrier is a better comparison. The vehicles involved have some intelligence and control unlike bullets.

Re:Just build it horizontally (1)

monkeythug (875071) | about 2 years ago | (#41157955)

Get the trajectory just right and maybe you could 'catch' the object in the end of the catapult and slow it down using the electromagnets in a manner similar to the regenerative braking used in electric cars?

Re:Just build it horizontally (0)

Anonymous Coward | about 2 years ago | (#41158113)

And get the trajectory just a bit not right and things gets messy!

Re:Just build it horizontally (1)

Bill, Shooter of Bul (629286) | about 2 years ago | (#41157781)

True, but there are mountains and craters and other geological things that need to be avoided. Its not like its a perfect marble.

Re:Just build it horizontally (1)

randall77 (1069956) | about 2 years ago | (#41157919)

Non-uniformity only helps you, as you can take advantage of it to orient your mass driver above horizontal. The problem with a mass driver is the generated orbit intersects the moon again quite quickly (unless you go for escape velocity?). You need to redirect the payload once it is launched, with its own rockets or some sort of catching mechanism.

Re:Just build it horizontally (1)

Mycroft_VIII (572950) | about 2 years ago | (#41158689)

Yep real good for launching grains and such from the lunar colonies, as long as you have a decent computer to run the whole thing.
      Though if you use convict labor things could get interesting.

Mycroft

Do these guys work for Lexmark? (0)

Anonymous Coward | about 2 years ago | (#41157605)

So, we'll build a space elevator on the Moon, See?

And we'll only charge $49 for the entire elevator ride, and only $1M for the trip there, See?

But the return trip fuel cartridges will be $1M a piece, and they'll need THREE OF THEM!

There is one problem... (4, Informative)

Nadaka (224565) | about 2 years ago | (#41157615)

That problem is that there is no way to create a lunar-centric orbit where the upper terminus of the ribbon hovers over a fixed position. So any tether can not be fixed to the ground. So lifting anything with that tether will involve something like a skyhook catch, except it will be at orbital velocities.

Re:There is one problem... (1)

MozeeToby (1163751) | about 2 years ago | (#41157731)

Which, at least in my opinion, makes it not a space elevator at all. After all, we could probably make a ribbon strong enough for an ultra sonic sky hook today or at least quite soon. A space elevator is a completely different ballgame. Using misleading buzzwords to get your funding off the ground is a bit of a red flag IMO.

Re:There is one problem... (0)

Anonymous Coward | about 2 years ago | (#41157779)

Yes there is. Since the same side of the moon always points toward the Earth , you could elevate the ribbon dead center on the "visible moon" and if it stretched high enough it could be drawn by Earths gravity into stability.

Re:There is one problem... (4, Informative)

david.given (6740) | about 2 years ago | (#41158117)

Having read TFA, this seems to be precisely what they're doing [gizmag.com] ; it looks like they deploy at the L1 point and extend the tether in both directions. Of course, this does mean the tether needs to be an extraordinary 250000km long.

Despite being totally awesome (which is reason enough to do it!) and also good practice for Earth (ditto) I am slightly at a loss as to how useful this would be. Space elevators are slow, and a lunar elevator would be really long and therefore really slow. And it's not as if the moon's hard to land or take off from.

I'm wondering if there's something useful to do with the other end. The high end of the tether is only 135000km from Earth. Is that far enough into the ionosphere to use for power generation?

Re:There is one problem... (2)

Score Whore (32328) | about 2 years ago | (#41158883)

And where is the counterweight going to go in case of an accident that severs the elevator?

Re:There is one problem... (1)

david.given (6740) | about 2 years ago | (#41159063)

I'm sorry, I don't follow you. Sever the elevator where? What are you expecting to happen/not happen?

Re:There is one problem... (4, Interesting)

ClickOnThis (137803) | about 2 years ago | (#41157827)

That problem is that there is no way to create a lunar-centric orbit where the upper terminus of the ribbon hovers over a fixed position.

Actually a Lagrange point would do fine for that. L1 is about 58,000 km [universetoday.com] from the moon towards the earth.

Re:There is one problem... (1)

Nadaka (224565) | about 2 years ago | (#41158029)

I hadn't considered that, it isn't strictly a lunar orbit.

And the length of cable would actually be as long as or longer than the cable required for an earth-geosynchronous orbit elevator (~36,000 km)

Re:There is one problem... (1)

ClickOnThis (137803) | about 2 years ago | (#41158101)

I hadn't considered that, it isn't strictly a lunar orbit.

And the length of cable would actually be as long as or longer than the cable required for an earth-geosynchronous orbit elevator (~36,000 km)

As others have pointed out here, it would need to be a bit longer still and with a mass at the end, in order to maintain tension on the cable.

Re:There is one problem... (1)

wonkey_monkey (2592601) | about 2 years ago | (#41158073)

Since the moon is tidally locked to the Earth, does that mean the geostationary point would have to be at an Earth-moon distance? Or do you mean that the moon's rotation is so slow that there is literally no "geo"stationary orbit above the moon?

Re:There is one problem... (1)

Nadaka (224565) | about 2 years ago | (#41158199)

I mean that there is no geostationary orbit within the moons hill radius. And orbits do not exist outside an objects hill radius, things outside the hill radius by definition orbit something else or are on a non orbital trajectory.

er.. does the moon rotate fast enough?? (1)

romanval (556418) | about 2 years ago | (#41157617)

woudln't you need a body that rotates fast enough (at the equator) to keep the elevator line taught?

Re:er.. does the moon rotate fast enough?? (0)

Anonymous Coward | about 2 years ago | (#41157753)

The moon does not rotate. When you look at the moon the same side of the moon always points to the earth. So, the ribbon would need to be held stable by Earths gravity to some extent (it seems).

Re:er.. does the moon rotate fast enough?? (3, Informative)

ClickOnThis (137803) | about 2 years ago | (#41157857)

The moon does not rotate. When you look at the moon the same side of the moon always points to the earth. So, the ribbon would need to be held stable by Earths gravity to some extent (it seems).

Our moon does rotate, with a period equal to its revolutionary period about the earth. This kind of synchronization is common with moons of planets, and is caused by tidal forces between the moon and the planet.

Re:er.. does the moon rotate fast enough?? (1)

fustakrakich (1673220) | about 2 years ago | (#41157863)

The moon does not rotate.

?? The lunar day is approximately 672 hours

Re:er.. does the moon rotate fast enough?? (1)

randall77 (1069956) | about 2 years ago | (#41157937)

The moon does rotate, just at the same speed that it orbits (once every ~28 days).

One other thing a Space Elevator needs... (4, Insightful)

yotto (590067) | about 2 years ago | (#41157667)

They're forgetting the single most important part of a space elevator: It needs to actually be useful.

What are we going to do with a space elevator on the moon? We don't go there for a very good reason: Its expensive as hell. Making the cheap and easy part a little cheaper an easier isn't going to change the fact that the entire rest of the trip is prohibitively expensive.

It's like your friend moving across town to be closer to you, but he lives in Seattle and you live in London.

Re:One other thing a Space Elevator needs... (1)

alphatel (1450715) | about 2 years ago | (#41157749)

They're forgetting the single most important part of a space elevator: It needs to actually be useful.

But we can use the ribbon to hurl the moon at Melancholia and save ourselves!

Re:One other thing a Space Elevator needs... (2)

Grishnakh (216268) | about 2 years ago | (#41157785)

We don't go there because we're shortsighted and stupid. There's plenty of things the Moon would be good for, such as astronomy, and especially mining. There's a lot of He3 there, which would be very valuable for fusion reactors.

Re:One other thing a Space Elevator needs... (2)

randall77 (1069956) | about 2 years ago | (#41157957)

First we need a fusion reactor.

Re:One other thing a Space Elevator needs... (4, Funny)

jfengel (409917) | about 2 years ago | (#41158145)

If we had helium fuel, we could have helium-fueled fusion energy, if we had a fusion reactor.

Re:One other thing a Space Elevator needs... (1)

bware (148533) | about 2 years ago | (#41158301)

There's plenty of things the Moon would be good for, such as astronomy, and especially mining. There's a lot of He3 there, which would be very valuable for fusion reactors.

The moon sucks for astronomy. It's covered with a particularly nasty form of dust, the temperature variations are extreme, and your telescope is in the blazing sunlight for two weeks at a time, so your duty cycle is horrible.

What can you mine on the moon that you can't mine on Earth for much cheaper? And by "much" I mean astronomically.

How about if we actually come up with working fusion device that uses He3 before we go start mining the mythical He3 on the moon?

Re:One other thing a Space Elevator needs... (1)

Grishnakh (216268) | about 2 years ago | (#41158519)

I'm sure the dust problem can be overcome with engineering. How much worse can the temperature extremes be than what our orbital telescopes have to deal with? As for sunlight, isn't that already a problem on Earth?

For mining, it's hard to say without actually going there and looking more closely. There's tons of stuff we mine now that it very rare and we could use more of. Even copper is getting more and more rare, as the prices for it keep rising greatly, and it's of critical importance to our technology. Lithium would be nice too. Plus, our existing mining processes cause enormous environmental devastation.

He3 on the moon isn't "mythical".

The moon would also be an excellent location for low-gravity manufacturing processes.

Re:One other thing a Space Elevator needs... (5, Informative)

bware (148533) | about 2 years ago | (#41159139)

Why deal with dust at all? Put your scope in space.

The temperature extremes are much worse on the moon - close to absolute zero to hundreds of K if my memory serves right . In space, you just put your scope at L2 or Earth-trailing, build a passive solar shield (or use a cryopump if you need really low temps), and point it away from the sun. Voila, constant temperature and 100% duty cycle. Put your scope in space.

There's also the fact that during the two weeks of duty cycle where you can operate the scope, you don't have solar power, so you have to have some way of storing energy. A telescope in space just uses solar panels and gets power 24/7. You'll have to cool your electronics half the time, and heat them the other half, so again, power, and storage. Go ahead, say nuclear. My understanding is that the moon has very few heavy elements, so all that has to come from Earth. So add a nuclear reactor, RTG, or batteries to your expenses.

Telescopes on the moon have to have pointing mechanisms, and the moon has gravity, so it's more mechanically complex (dust, vacuum). Telescopes in space have reaction wheels and thrusters to control pointing. No dust, and also few moving parts in vacuum. Much simpler. Put your telescope in space.

That is, in fact, why we are putting our telescopes out at L2 or Earth-trailing. Hubble would have been there had it not been for the mandate that it ride the shuttle. Have you noticed that we're not putting telescopes in Earth orbit anymore? It's not because we don't have the shuttle. It's because Earth orbit is sub-optimal, and not just a little bit.

As far as comparing astronomy on the moon to astronomy on Earth, well, Earth has a lot of advantages for telescopes, and that's why there are lot more of them here on Earth than there are in space. Not least that you can breath the atmosphere and find cheap places to sleep and have grad students pull the late night shifts. There are of course disadvantages, and you could never have JWST on the ground, but the moon is just not a great place for telescopes. I'm not entirely talking out of my ass here. I've sat in the rooms where these tradeoffs were made, and the moon gets put on the list. Then we start ranking. The moon ranks low in performance (duty cycle, power), high in cost (humans in space suits have to build it, everything has to be shipped from Earth), and high in risk (you have to ask why, srsly?). Then by the wonders of Excel, the moon drops to the bottom of the rankings.

But it is considered.

That's even assuming we had the capability to build a telescope on the moon. Which would be insanely expensive. Humans building telescopes, launchable or not, where they can breathe is always going to be way cheaper than building them on the moon.

Care to link to any peer-reviewed documentation that shows the abundance of He3, or any other interesting mine-able elements on the moon? I am ignorant of the geology of the moon, so if there's evidence that there are mine-able elements on the moon (including He3), I'd be happy to have my ignorance lessened.

You haven't really addressed the question of you know, actually having a working fusion reaction that needs He3. We don't. And probably won't any time soon. What are the economics of mining something we don't yet need and is difficult to store?

Re:One other thing a Space Elevator needs... (0)

Anonymous Coward | about 2 years ago | (#41158841)

Just paving the lunar desert with in-situ manufactured solar panels might be a better idea, at least in the short term. Should get you quite a lot of power - to manufacture more panels... :)

Re:One other thing a Space Elevator needs... (1)

Iskender (1040286) | about 2 years ago | (#41157939)

What are we going to do with a space elevator on the moon? We don't go there for a very good reason: Its expensive as hell. Making the cheap and easy part a little cheaper an easier isn't going to change the fact that the entire rest of the trip is prohibitively expensive.

For the Apollo missions, they needed their rockets to use fuel to lift the fuel that carried the payload that was fuel for the lunar descent to retard the fuel needed to lift the fuel for the ascent. It gets complicated pretty quickly.

Absolutely none of this was of course free, and the most expensive substances were those at the lunar end - every gram has a much larger fuel equivalent at the start of the process.

It will still be expensive to go there even with the elevator, but any reduction in price will inevitably create new applications. The obvious example being sample return: scientists want all the moon they can get, and rock from a single point on the equator will do just fine.

Re:One other thing a Space Elevator needs... (2)

symbolset (646467) | about 2 years ago | (#41159393)

A company named Planetary Resources is working on this. They're in Seattle.

Re:One other thing a Space Elevator needs... (1)

p0p0 (1841106) | about 2 years ago | (#41157993)

No, it's more like you living in London and him in Seattle, then building a tunnel between your houses that takes half the time and cost to travel between the 2, no too mention is is easier then catching 3 connecting flights and a submarine to Atlantis before the UFO transfer and bomb drop to Seattle after which you still need to ride in a cab.

It is significantly easier and cheaper, much more than you are making it out to be.

Re:One other thing a Space Elevator needs... (0)

Anonymous Coward | about 2 years ago | (#41158105)

London? More like "he lives on the Moon!"

Re:One other thing a Space Elevator needs... (1)

DerekLyons (302214) | about 2 years ago | (#41158833)

They're forgetting the single most important part of a space elevator: It needs to actually be useful.

This is Micheal Laine you're talking about here - useful is optional and definitely secondary to his Vision of a Glorious Future.
 
Did they ever get around to repossessing his 'factory' in (IIRC) New Jersey? He's come a long way from shilling for dodgy tech based initiatives, but that's long been his pattern - when one scheme falls apart, move on to another even more dubious one.

..ok, how? (4, Interesting)

kheldan (1460303) | about 2 years ago | (#41157675)

Wouldn't we need to get back to the Moon, establish some sort of colony there, and create the industry and infrastructure just to build such a thing in the first place? I can't see this all happening in the next 8 years.

Re:..ok, how? (1)

Grishnakh (216268) | about 2 years ago | (#41157819)

Seems like the biggest challenge would be building the cable and satellite; the work you have to do on the Moon should be minimal, mainly just anchoring the cable after it's dropped from the satellite. Of course, afterwards you'd want to build a base or something, but just to get the elevator working that isn't strictly necessary. The cable would be built on Earth. After this is all done and in place and a base is established, and mining operations started up, then we can start building up infrastructure and manufacturing operations there.

Re:..ok, how? (2)

Svippy (876087) | about 2 years ago | (#41159053)

Simple! They build the elevator on Earth, then strap it to a rocket that they fly directly into the moon. Fortunately, they have turned the elevator upside down, so when the rocket crashes into the moon, the elevator stands upward.

This is kinda like how they build skyscrapers: Build it lying down, then straight it up when it's done. Much cheaper and safer.

no way (0)

Anonymous Coward | about 2 years ago | (#41157719)

no. fucking. way

Then what? (0)

Anonymous Coward | about 2 years ago | (#41157733)

We'll still need to use old fashioned rockets to get stuff to the moon before we can launch it–again–from the moon!

Seems backwards to me. If the big hurdle getting out of Earth's gravity well, then once something is in space, the marginal energy needed to go to, say, Mars, is relatively small isn't it? Compared to going to the Moon first, then to Mars?

And do we really need unobtanium for an Earth-based elevator? Aren't carbon nanotubes theoretically up to the task? We just need to perfect industrial scale production of nanotubes.

Re:Then what? (1)

rickb928 (945187) | about 2 years ago | (#41157927)

License it from Oakley [wikipedia.org] , and you can try it out.

Doesn;t seem suitable, but it has so many different properties and uses in eyeglasses, who knows? Might work.

Lunar Musaz (1)

Grayhand (2610049) | about 2 years ago | (#41157775)

I can just see the cable breaking and some fool tries the stunt of jumping just before it hits. Given the gravity I wonder just how much force his head would have when it hit the ceiling? A study of that could be worthy of an ignoble award.

LIftport,, Can You Hear Me Major Tom (1)

dontgetshocked (1073678) | about 2 years ago | (#41157803)

Can you hear me Major Tom,,, Here I am drifting in a tin can.

moon-stationary orbit, correct me if I'm wrong (1)

Arthur B. (806360) | about 2 years ago | (#41157889)

google: ( ( lunar cycle / 2*pi)^2 * mass of the moon * gravitational constant )^(1/3)
That's 429,000km .. 1.12x the earth moon distance. Uhhh

Re:moon-stationary orbit, correct me if I'm wrong (0)

Anonymous Coward | about 2 years ago | (#41159247)

If the moon were alone in space, yes, that's correct. But we've got another big planet right next door, so you can use it's gravity to provide the additional pull on the station. You only need to get a little ways past the L1 point.

Who is going to use this? (0)

Anonymous Coward | about 2 years ago | (#41157943)

So, who is going to use the? You need to get ppl from earth to moon first, and while doing that, why land on the moon first? The moon squirrels will send off scout recons to titan?

How about a Mass Driver? (0)

Anonymous Coward | about 2 years ago | (#41158011)

A mass driver in addition to (or instead of) this on the moon would be easier to build and more beneficial. We can get stuff to and from the moon just fine. It's getting further than the moon that's a big problem.

Good luck (2)

moniker127 (1290002) | about 2 years ago | (#41158263)

"settling for a more modest goal – building an elevator on the Moon"
Did someone just use the words "settle" and "building on the moon" in the same sentence? Who are these people?
Where are the billions of dollars this is going to take? How the hell are they going to prototype it?
Do they realize that 2020 isn't some lofty far off time these days? That's a bit more than 7 years.

If NASA, Russia, or China (or Elon Musk) said they were going to try this, I'd be excited. But this shit is not going to happen like this, lets just be honest.

Re:Good luck (1)

chriso11 (254041) | about 2 years ago | (#41158637)

I think it makes more sense to make a space elevator from LOE. All the advantages of a lunar elevator, but actually in a useful location,

Somehow relevant... (1)

twotacocombo (1529393) | about 2 years ago | (#41158277)

Reservationist: Oh, I can reserve you a flight coming back from Chicago at 5:55. Does that help? Richard: Hi, I'm Earth. Have we met? Reservationist: I don't think so.

Business Plan (1)

Anonymous Coward | about 2 years ago | (#41158467)

Step 1: Build space elevator on the moon.

Step 2: ??

Step 3: ???

Step 4: ????

Step 5: PROFIT!!!

Alternative architecture (0)

Anonymous Coward | about 2 years ago | (#41158815)

Instead of a 'static' ribon or cable with cars climbing up and down, instead make the ribbon itself movable.

The payload will be attached to one end of the ribbon, and then the *entire* ribbon will be lowered until the end is near the ground and the payload can be swapped with the next upbound payload.

As the ribbon moves up, the other end can either be played out further into a higher orbit to help balance the forces, or it could be wound onto a reel. (The first is probably better, energetically speaking).

I think this idea has good potential.

Space elevator to the moon (0)

Anonymous Coward | about 2 years ago | (#41158859)

Use bricks and mortar.
How could you attach anything to an object that revolves around us/

geostationary ? (1)

p51d007 (656414) | about 2 years ago | (#41159401)

Unless the moon & earth are in a geostationary orbit, won't this think drift around? I guess having it "anchor" in space will negate that problem?
Load More Comments
Slashdot Login

Need an Account?

Forgot your password?
or Connect with...

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>